不同体系聚羧酸减水剂的合成与性能研究

发布时间：2018-06-23 04:32

  本文选题：聚羧酸减水剂 + 流动度　； 参考：《沈阳建筑大学》2014年硕士论文

【摘要】：随着建筑行业的迅猛发展,在工程应用中对于混凝土外加剂的要求逐步提高,为了满足不同施工要求,不同种类的混凝土外加剂相继研发。作为混凝土外加剂,聚羧酸系减水剂具有减水率高、分散性、坍落度保持性好、提高混凝土强度、降低水泥使用量、功能可控等优点,因此了解不同官能团对聚羧酸减水剂的影响具有重要的意义。本论文合成了APEG-AA、APEG-MMA-AA、APEG-SMAS-AA、APEG-MA-AA、APEG-AM-AA五种不同体系的聚羧酸减水剂,并对它们的技术性能、水泥水化速率等进行了研究。对于APEG-AA体系聚羧酸减水剂,以APEG为反应单体的减水剂的减水效果优于以TPEG为反应单体;流动度随APEG与AA摩尔比的增大先增大后减小,n(APEG)∶n(AA)=1.00∶3.27为最佳摩尔比;流动度随活性调节剂掺量的增加而增加,活性调节剂的掺量为大单体质量的0.15%时最好,随后流动度随着掺量的增加而降低;通过正交试验发现,当反应温度为60℃,反应时间为4.5h,引剂用量为大单体质量的2.0%时,得到的APEGAA体系聚羧酸减水剂的减水效果和保塑性最好。对于APEG-MMA-AA体系、APEGSMAS-AA体系、APEG-MA AA体系和APEG-AM AA体系聚羧酸减水剂,流动度随不同反应原材料取代AA摩尔的增加、反应温度的升高和反应时间的增加而先增加后减小,最终确定:取代AA摩尔的20%、温度70℃、时间4.5h为最佳合成条件。对五种不同体系的聚羧酸减水剂进行技术性能的测试,五种不同体系聚羧酸减水剂的固含量分别为42.7%、39.9%、41.5%、44.3%、41.4%,胶砂减水率分别为37.6%、38.2%、38.5%、39.4%、37.5%,饱和点均为0.20%,且与不同品种的水泥适应性较强,表现出较好的减水和分散效果。通过红外光谱测试,确认了不同体系聚羧酸减水剂分子结构中应存在羧基(-COOH)、醚基(-O-)、羟基(-OH)、C-H键等官能团。对合成的不同体系聚羧酸减水剂的水泥净浆凝结时间、胶砂强度和水泥水化速率进行了测试。甲基具有较好的缓凝性能;酰胺基具有一定的早强效果;磺酸基、酰胺基具有良好的保塑性。通过测试不同体系聚羧酸减水剂的水泥水化速率曲线可知,出现水化速率峰的顺序依次是APEG-AM-AA体系、APEG-AA体系、APEG-SMAS-AA体系、APEG-MMA-AA体系和APEG-MA-AA体系,结果与水泥净浆凝结时间和胶砂强度的测试结果基本相符。
[Abstract]:With the rapid development of the construction industry, the requirements for concrete admixtures have been gradually raised in engineering applications. In order to meet different construction requirements, different kinds of concrete admixtures have been developed one after another. As a concrete additive, polycarboxylic acid superplasticizer has the advantages of high water reducing rate, high dispersion, good slump retention, increasing concrete strength, reducing cement usage, controllable function, etc. Therefore, it is of great significance to understand the effect of different functional groups on polycarboxylic acid superplasticizer. In this paper, five kinds of polycarboxylic acid water reducers of APEG-AAA, APEG-MMA-AA, APEG-SMAS-AAN, APEG-MA-AM-AA have been synthesized, and their technical properties and hydration rate of cement have been studied. For APEG-AA polycarboxylic acid superplasticizer, the water reducing effect of water reducing agent with APEG as reactive monomer is better than that with TPEG.The mobility increases first with the increase of the molar ratio of APEG to AA and then decreases with the increase of the molar ratio of APEG to AA, and then decreases to 1.00: 3.27 as the optimum molar ratio. The fluidity increased with the increase of the amount of active modifier, and the content of active modifier was the best when the mass of macromonomer was 0.15, then the fluidity decreased with the increase of the amount of active modifier, and it was found by orthogonal experiment that the reaction temperature was 60 鈩，

本文编号：2055787